Open assembly file error.

Hi everybody

Recently, update to SW2011. for some project, after few days running(use SW2011 open sw2010, and save), then open some main asm file shows following error,

it's so serious problem, it's affected our two projects, we need to re-do asm.  Anybody can help to solution?

I also have sent to Solidwork side, still waiting their answering,

SolidworksAssemblies